JP7219132B2 - Cooling water passage of internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling water passage for an internal combustion engine.

2. Description of the Related Art In internal combustion engines for automobiles and the like, a cylinder block and a cylinder head are cooled with cooling water. That is, the cylinder block is formed with a cooling water passage (block jacket) surrounding a group of cylinder bores, while the cylinder head is formed with a cooling water passage (head jacket) that spreads over the entire surface of the water pump. The cooling water pumped by is sent to the block jacket and head jacket.

A water pump is generally driven by a crank pulley through an accessory drive belt. Therefore, the water pump is arranged in the front part of the cylinder block near the timing chain, or in the front cover that covers the timing chain.

Patent Document 1 discloses an example in which a water pump is arranged in front of a cylinder block. In Patent Document 1, a water pump housing has an L-shaped discharge passage in a plan view, and a cylinder block has an inlet communicating with the discharge passage. Therefore, the passage located downstream of the water pump is composed of two passages perpendicular to each other.

JP 2015-145631 A

When the cooling water passage on the downstream side of the water pump is formed in an L shape as in Patent Document 1, the passage formed in the cylinder block opens in a direction orthogonal to the side surface of the cylinder block, so it is formed by casting. Even if it is formed by drilling, the processing is easy (particularly, drilling is preferable because the drill does not slip).

However, in the configuration in which the cooling water passages are merely perpendicular to each other, the flow direction of the cooling water abruptly changes at the intersections, which causes a problem of large flow resistance and large pressure loss.

Regarding this point, it is conceivable to round the outer corners of the intersection to guide the cooling water toward the cylinder block, but even if rounded, there is a limit to the size, so the pressure loss can be greatly reduced. It is doubtful whether it will reach In addition, if the area of the flow path is reduced by rounding, the flow speed of the cooling water will increase, and there is a risk of violent collision with the corners, which will greatly reduce the guide function of the roundness. It could be.

The invention of the present application was made in response to such a situation, and is intended to greatly reduce the pressure loss with a simple structure.

The claimed invention is
"A part of the passage through which the cooling water discharged from the water pump flows is in a state in which the first passage located upstream and the second passage located downstream in a posture perpendicular to the first passage are in communication. is forming
In the configuration
"The first passage and the second passage are arranged in a direction orthogonal to the axis of both passages so that the cooling water flowing from the first passage into the second passage becomes a swirling flow inside the second passage. is offset and
A thermo valve having a movable valve plate that moves in an axial direction of a central axis due to expansion and contraction of a temperature sensing portion is arranged in the second passage in a posture in which the central axis is parallel to the second passage. The water is swirling around the central axis of the thermo valve. ”
It has the characteristics of

Although there is no limitation to the offset mode between the first passage and the second passage, if the first passage and the second passage are in a horizontal posture as in Patent Document 1, the second passage may be positioned below the first passage. and a mode in which the second passage is offset above the first passage. When the second passage is offset below the first passage, gravity promotes the swirl flow of the cooling water, which is efficient.

In the present invention, the cooling water discharged from the first passage forms a swirling flow inside the second passage and smoothly moves to the back. In this case, since it is a simple structure in which the first passage and the second passage are offset, the cost does not increase. In addition, since the flow passage area does not decrease, there is no problem that the flow velocity increases and the effect of the swirling flow is reduced.

Therefore, in the present invention, it is possible to maintain the first passage and the second passage in a substantially orthogonal posture, and to smoothly supply the cooling water with significantly reduced pressure loss at low cost, and improve fuel efficiency. can also contribute to

Further, in the present invention, cooling water can be evenly applied to the temperature sensing portion of the thermovalve arranged in the second passage, so there is an advantage that the responsiveness of the thermovalve can be significantly improved. In addition, since the cooling water turns into a swirling flow and is evenly mixed in the second passage, the temperature sensing portion of the thermo valve can be brought into contact with the cooling water that is evenly mixed and has a uniform temperature. , the responsiveness of the thermo-valve can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment, (A) is a schematic diagram which shows a cooling system, (B) is a sectional view seen from IB-IB of FIG. It is a top view. It is the top view which separated the water pump. It is a side view seen from a direction perpendicular to the crank axis and the cylinder bore axis. It is the side view which separated the water pump. It is a VI-VI sectional view of FIG. 4 (the cross section of a water pump is not displayed.). It is a plane sectional view showing the cross section of the water pump. FIG. 5 is a sectional view taken along line VIII-VIII in FIG. 4; 9 is a sectional view taken along line IX-IX of FIG. 8; FIG.

Next, embodiments of the present invention will be described based on the drawings. In the following, the terms front-rear and left-right are used to specify the direction, but the front-rear direction is the direction of the crank axis (longitudinal direction of the cylinder block), and the left-right direction is the direction perpendicular to the crank and cylinder axes (short direction of the cylinder head). hand direction). Regarding the front and rear, the side where the timing chain is arranged is the front, and the side where the transmission is arranged is the rear. Just to make sure, the directions are clearly shown in FIG. 2 and the like.

The vertical direction is the cylinder bore axis. Therefore, the plane view is the direction seen from the cylinder bore axis direction, and the side view is the direction seen from the crank axis direction and the direction perpendicular to the cylinder bore axis.

(1). Overview of Internal Combustion Engine This embodiment is applied to a vehicle internal combustion engine. First, the outline of an internal combustion engine will be described based on the schematic diagram of FIG. 1(A).

The internal combustion engine comprises a cylinder block 1 as the core of the engine body and a cylinder head 2 fixed on the upper surface thereof. A cylinder head cover 3 is fixed on the upper surface of the cylinder head 2, and a An oil pan 4 is fixed. A front cover (chain cover, chain case) 5 covering a timing chain (not shown) is fixed with bolts to the front surfaces (one end surfaces) of the cylinder block 1 and the cylinder head 2 .

A block jacket 6 is formed in the cylinder block 1 so as to open upward toward the cylinder head 2 , and a head jacket 7 is also formed inside the cylinder head 2 . The cylinder block 1 and the cylinder head 2 are each cast aluminum.

A water pump 8 is arranged near the front end of the cylinder block 1, and cooling water is supplied from the water pump 8 to the block jacket 6 and the head jacket 7. A two-path cooling system is adopted in which the cooling water mainly flows to the head jacket 7 when the temperature is lower than the temperature, and flows to both the head jacket 7 and the block jacket 6 when the cooling water reaches the set temperature .

Therefore, the head-bound water supply passage 10 and the block-bound water supply passage 11 are branched from the discharge passage 9 of the water pump 8, and the first thermo valve 12 is arranged in the block-bound water supply passage 11. communicates with the front end portion of the head jacket 7 , and the block-bound water supply passage 11 communicates with a portion near the front end of the block jacket 6 .

A cooling water outlet 2a is opened at the rear end of the cylinder head 2, and a heater feeding pipe 13 and a radiator feeding pipe 14 are connected to the cooling water outlet 2a. The heater feed pipe line 13 is connected to the inlet port of the heater core 15, but an EGR cooler 16 is interposed in the middle. A heater return line 17 is connected to the outlet port of the heater core 15 , and the heater return line 17 is connected to a relay portion 18 formed at the rear end portion of the cylinder head 2 .

An oil cooler 19 is inserted in the middle of the heater return line 17 . The heater feed line 13 and the heater return line 17 are connected by a bypass passage 20, in which an EGR valve 20a is interposed.

A relay portion 18 formed at the rear end portion of the cylinder head 2 is formed with a head flow passage 21 that opens toward the rear end portion of the cylinder block 1 . and the water pump 8 are formed integrally with each other.

On the other hand, the radiator feed line 14 is connected to the upper tank of the radiator 23 , and the radiator return line 24 is connected to the lower tank of the radiator 23 . A second thermo valve 26 is arranged in a relay passage 25 communicating with the downstream end of the cooling water return passage 22 , and a port of the second thermo valve 26 is connected to the radiator return passage 24 .

When the temperature of the cooling water is lower than the set value, all of the cooling water flows through the heater return pipe 17 and into the cooling water return passage 22 . On the other hand, when the temperature of the cooling water exceeds the set value, most of the cooling water discharged from the head jacket 7 is sucked into the water pump 8 via the radiator 23, and the rest is transferred to the heater return pipe 17 and The coolant is sucked into the water pump 8 via the cooling water return passage 22 .

(2). Basic Structure of Cylinder Block Next, the details of the cooling water flow structure related to the cylinder block 1 will be described with reference to FIG.

The internal combustion engine of this embodiment has three cylinders, and therefore, as shown in FIG. A group of cylinder bores 27 is surrounded by a block jacket 6. In this embodiment, the block jacket 6 is separated into a front block jacket 6a forming a front portion and a main block jacket 6b.

When the temperature of the cooling water is lower than the set temperature, the cooling water flows only from the front block jacket 6a to the head jacket 7. When the temperature of the cooling water exceeds the set temperature, the cooling water flows as shown in FIG. It flows from the main block jacket 6b to the head jacket 7 via the communication holes 28 shown.

The internal combustion engine of this embodiment is for a vehicle and is mounted in an engine room. is installed in the vehicle. As shown in FIG. 2, a cooling water inlet 30 that communicates with the head flow passage 21 shown in FIG. Further, on the near side of the cooling water inlet 30, a first block side oil dropping passage 31 and a second block side oil dropping passage 32 are formed in a state of being aligned in the front-rear direction.

Both block-side oil dropping passages 31 and 32 pass through the cylinder block 1 in the vertical direction, and an enlarged portion 33 extending in the front-rear direction is formed in the upper portion thereof. As indicated by dotted lines in FIG. 2, the cylinder head 2 is formed with two front and rear head-side oil dropping passages 34 and 35 corresponding to the block-side oil dropping passages 31 and 32 . Reference numeral 36 shown in FIGS. 2, 3, etc. is a head bolt insertion hole.

For example, as shown in FIGS. 2, 3, and 1B, the exhaust side surface 29 of the cylinder block 1 is integrally formed with a horizontally long cylindrical boss body 37 that is elongated in the front-rear direction. It forms the cooling water return passage 22 described above. As shown in FIG. 6 , the cooling water inlet 30 and the rear end of the cooling water return passage 22 communicate with each other through a horizontal hole 38 . Further, as shown in FIG. 6, the rear end of the cooling water return passage 22 is closed with a plug 39. As shown in FIG.

As shown in FIG. 4 , the block-side oil dropping passages 31 and 32 are formed at a vertically long boss body 40 projecting from the exhaust side surface 29 of the cylinder block 1 . Therefore, the rigidity of the cylinder block 1 is enhanced by the oblong boss body 37 formed with the cooling water return passage 22 and the vertically oblong boss body 40 formed with the block-side oil dropping passages 31 and 32 . An auxiliary rib 41 for reinforcement protrudes from the exhaust side surface 29 of the cylinder block 1 .

(3) Water pump and suction structure As shown in Figs. The chamber 22a is opened sideways, and the water pump 8 is arranged with the expansion chamber 22a blocked.

As shown in FIG. 7, the water pump 8 includes a main housing 44 having a relay passage 25 communicating with the expansion chamber 22a of the cooling water return passage 22, a cap 45 fixed to the main housing 44 from the side, a main housing 44 and includes a pump housing 47 that closes a pump chamber (vortex chamber) 46, and a pulley 49 that is rotatably held in the pump housing 47 via a bearing 48. An impeller 51 arranged in the pump chamber 46 is fixed to the main shaft 50 .

A pump chamber 46 is formed in the main housing 44 . The main housing 44 is fixed to the receiving seat 1a (see FIG. 5) of the cylinder block 1 with bolts, and the pump housing 47 and the cap 45 are each fixed to the main housing 44 with bolts. Needless to say, the water pump 8 is driven by a crank pulley via an accessory drive belt.

As shown in FIG. 7, the cap 45 is formed with a return port 45a that is open to the left and right, and the return port 45a is connected to the radiator return line 24 made of a hose. A second thermovalve 26 for controlling water flow to the radiator 23 is arranged in a space surrounded by the main housing 44 and the port cap 45 .

As shown in FIG. 7, the second thermovalve 26 includes a valve seat plate 54 sandwiched and held between the main housing 44 and the port cap 45, and a front cage 55 fixed to the valve seat plate 54 and projecting outward in the left-right direction. , a left-right longitudinal central shaft 56 fixed to the tip of the front cage 55 , a slider 57 located on the back side of the valve seat plate 54 and slidably attached to the central shaft 56 , and It has a fixed valve seat plate 54 and a movable valve plate 58 that can be brought into close contact with or separated from the valve seat plate 54. The movable valve plate 58 is moved by a spring 60 supported by a rear cage 59 fixed to the valve seat plate 54. It is biased in the direction of coming into close contact with 54 .

The valve seat plate 54 has a water passage hole, and the cages 55 and 59 also have a water passage structure. The slider 57 incorporates a temperature-sensitive body that expands and contracts according to temperature. is in close contact with the valve seat plate 54 . Therefore, circulation of cooling water to the radiator 23 is stopped.

On the other hand, when the temperature of the cooling water reaches the set value, the temperature-sensitive effector thermally expands and the slider 57 begins to retreat, thereby separating the movable valve plate 58 from the valve seat plate 54 . Therefore, the cooling water circulates through the radiator 23 . As the temperature of the cooling water rises from the set temperature, the amount of water flowing to the radiator 23 increases as the amount of movement of the movable valve plate 58 increases.

A valve seat plate 54 of the second thermovalve 26 separates the relay passage 25 from the return passage 52 , and the cooling water is sucked from the relay passage 25 into the pump chamber 46 . As indicated by an arrow 61 in FIGS. 7 and 9, the cooling water flows into the pump chamber 46 from the direction of the rotational axis of the impeller 51, flows in the circumferential direction of the pump chamber 46, As indicated by 9, it reaches a longitudinally elongated discharge passage 9 formed in the lower portion of the main housing 44. As shown in FIG.

As shown in FIG. 7, the intermediate passage 25 connecting the expansion chamber 22a of the cooling water return passage 22 and the pump chamber 46 of the water pump 8 is formed with a constricted portion (constricted portion) 66 having a reduced cross-sectional area and is expanded. The axis O1 of the chamber 22a and the axis O2 of the second thermovalve 26 (of the relay passage 25) are offset by a certain amount of dimension E in the longitudinal direction so that the center of the second thermovalve 26 is shifted forward. ing.

By providing the narrowed portion 66, it can be said that the space outside the narrowed portion 66 in the relay passage 25 becomes a temperature sensing space 25a in which the temperature sensing portion of the second thermovalve 26 is arranged. The expansion chamber 22a is formed substantially circular in side view, while the relay passage 25 is also formed circular in side view, and both inner diameters are set to be substantially the same. The cross-sectional area of the relay passage 25 is narrowed down to about half by the narrowed portion 66 . The back side of the narrowed portion 66 is a smooth curved surface 66a.

When the throttle portion 66 is formed in the relay passage 25, as indicated by a solid arrow 68 in FIG. , and then passes through the constricted portion 66, the temperature-sensitive space 25a diffuses in the radial direction of the center line of the constricted portion 66 while decreasing the flow velocity. In addition, since the cooling water is sufficiently mixed in the expansion chamber 22a to have a uniform temperature, the cooling water having a uniform temperature can be evenly brought into contact with the temperature sensing portion of the second thermovalve 26.例文帳に追加As a result, the responsiveness of the second thermovalve 26 can be improved.

(4) Structure of Discharge from Water Pump As shown in FIG. are in communication. As shown by the solid line in FIG. 8, the horizontally elongated portion 11a of the block-bound water supply passage 11 is formed so as to straddle the main housing 44 and the cylinder block 1. ) communicates with the vertically elongated portion 11b of the block-bound water supply passage 11, and the vertically elongated portion 11b communicates with the front end portion of the main block jacket 6b.

As indicated by the dashed line in FIG. 8, the horizontally elongated portion 10a of the head-bound water supply passage 10 is also formed so as to straddle the main housing 44 and the cylinder block 1. A vertically elongated portion 10b communicating with the block jacket 6a is in communication.

2, 3 and 6 also clearly show the head-bound water supply passage 10 and the block-bound water supply passage 11 . As described above, the horizontally elongated portion 10a of the head-bound water supply passage 10 and the horizontally elongated portion 11a of the block-bound water supply passage 11 are also formed in the cylinder block 1. In FIG. Parts 10a and 11a are clearly shown.

A first thermovalve 12 is arranged in the horizontally elongated portion 11a of the block-bound water supply passage 11. As shown in FIG. The first thermo-valve 12 has a valve seat plate 54, a front cage 55, a central shaft 56, a slider 57, a movable valve plate 58, and a spring 60, similarly to the second thermo-valve 26. is sandwiched and fixed between the cylinder block 1 and the main housing 44 . However, in this first thermovalve 12 , the spring 60 is supported by a flange 64 fixed to the central shaft 56 .

In this embodiment, the discharge passage 9 of the water pump 8 corresponds to the first passage, and the horizontally elongated portion 11a of the block-bound water supply passage 11 corresponds to the second passage. As shown in FIG. 8, the discharge passage 9 of the water pump 8 is longitudinally elongated, while the horizontally elongated portion 11a of the block-bound water supply passage 11 is transversely elongated. Since they intersect at right angles, there is a problem that the pressure loss increases if the heights of both are the same.

Regarding this point, in this embodiment, as shown in FIG. It is offset downward (lowered). With this configuration, the cooling water discharged from the discharge passage 9 changes its direction downward and flows along the inner peripheral surface of the laterally elongated portion 11a, forming a swirling flow around the axis of the laterally elongated portion 11a. , smoothly flows toward the inner part of the laterally elongated portion 11a.

Therefore, flow resistance is remarkably reduced, and pressure loss can be greatly suppressed. As a result, the cooling performance of the engine can be improved, and the load on the water pump 8 can be reduced, contributing to improved fuel efficiency. In addition, since the cooling water becomes a swirling flow in the laterally elongated portion 11a, the straightness of the cooling water disappears. 12 responsiveness can be improved.

When the cooling water flow turns into a swirling flow, the cooling water mixability increases, which contributes to the uniformity of the cooling water temperature. This aspect also contributes to improving the responsiveness of the first thermovalve 12 . In the embodiment, the horizontally elongated portion 11a of the block-bound water supply passage 11 is offset to the lower side of the discharge passage 9, but even if the horizontally elongated portion 11a is offset to the upper side of the discharge passage 9, the same effect can be obtained.

The offset dimension of the laterally elongated portion 11a with respect to the discharge passage 9 can be set arbitrarily. Since the cooling water spouted from the nozzle is directed in the tangential direction of the laterally elongated portion 11a, the flow of the cooling water is further smoothed, which is effective in suppressing the pressure loss.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, it can be applied not only to the discharge passage and the block-bound water supply passage, but also to other portions.

The present invention can be embodied in a cylinder block of an internal combustion engine. Therefore, it can be used industrially.

Reference Signs List 1 cylinder block 6 (6a, 6b) block jacket 7 head jacket 8 water pump 9 discharge passage (first passage in the claim)
10 head-bound water supply passage 11 block-bound water supply passage 11a horizontally elongated portion (second passage in claims)
11b vertical portion 12 first thermo valve 22 cooling water return passage 44 main housing 46 pump chamber 47 impeller 49 pulley
56 central axis
57 Slider with built-in temperature sensing part
58 Movable valve plate

Claims (1)

A part of the passage through which the cooling water discharged from the water pump flows is formed in a state in which a first passage located upstream and a second passage located downstream perpendicular to the first passage communicate with each other. A configuration that
The first passage and the second passage are offset in a direction orthogonal to the axis of both passages so that the cooling water flowing from the first passage into the second passage becomes a swirling flow inside the second passage. being
A thermo valve having a movable valve plate that moves in an axial direction of a central axis due to expansion and contraction of a temperature sensing part is disposed in the second passage in a posture in which the central axis is parallel to the second passage. water is swirled around the central axis of the thermo valve,
A cooling water passage for an internal combustion engine.

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